Resonant chamber for accordions



March 28, 1950 A. FRONTALINI RESONANT CHAMBER FOR ACCORDIONS 2 Sheets-Sheet 1 Filed 001 l, 1948 A rom Ex March 28, 1950 A. FRONTALINI RESONANT CHAMBER FOR ACCORDIONS Filed Oct, 1, 1948 2 Sheets-Sheet 2 INVENTOR.

ATTORNEY.

Patented Mar. 28, 1950 Alfredo Frontalini, Numana, Italy Application October 1, 1948, Serial No. 52,339 In Italy March 6, 1948 Claims.

The present invention relates generally to airpressure-operated musical reed instruments, such as accordions, and particularly to resonant means for improving the tone quality and for augmenting the tone volume of such instruments and for reflecting sound from such instruments to without thereof.

The usual construction of accordions comprises two relatively fixed compartments, in one of which the treble reed elements are housed, while the base reed elements are located in the other fixed compartment. Connecting the two fixed compartments is an expansible compartment or bellows which supplies the necessary air under pressure to operate the several reed elements. Very little thought has been given to improving the tone quality and the volume of here tofore known instruments of this kind.

The general purpose of the present invention is to incorporate long overdue refinements in accordions to the end of enhancing their tone quality as well as their volume of sound emanating from the air-pressure-operated reed elements, whereby an overall improvement in the sound effects of such instruments is achieved. The means whereby such overall improvement in sound effects is accomplished are relatively simple. They comprise substantially resonant chambers of fixed volumes composed of what may be termed resonant exterior chamber portions and resonant interior or sound reflecting members.

The exterior portions are substantially oblong and have finely executed walls, the interior faces of which are smooth. The walls are curved so that the exterior open ends of the chamber portions are substantially smaller than their interior ends. Arranged in proper corelation with these exterior chamber portions are relatively thin walled, smooth faced, highly resonant interior chamber portions, to be known as sound reflecting members. The latter comprise substantially oblong, continuous, relatively deeply dished and also finely executed structures with smoothly finished walls. All corners and the edges at their open ends are curved. ihese sound reflecting members partly surround and are spaced from the reed blocks supporting the reeds, and are also uniformly spaced from the walls of the exterior chamber portions located in the fixed compartments. In these latter compartments are arranged partitions or boards forming reed block supporting members to which the reed blocks are fixedly secured. These portions have a plurality of valve-controlled openings.

The resonant sound reflecting members are delients extending from the reed block supporting" members. These suspending elements are so arranged that they hold the sound reflecting members at the desired uniform spacing from the walls of the fixed chamber portions. The edges at the open ends of the sound reflecting members are substantially parallel with at least some portions of the walls of the fixed chamber portions and, due to their floating suspension, are substantially free and are capable to respond unrestrictedly to sound vibrations.

As stated, in one of the fixed compartments of the instrument there are located reed blocks carrying the treble reeds. These reeds are operated from an exterior keyboard, while the base reeds mounted in the other fixed compartment are operated by means of another keyboard. The supporting member for the base reed blocks divides the fixed compartment into a relatively deep outer and a relatively shallow interior portion, whereas the supporting member for the treble reed blocks forms so-to-speak an outer wall of the compartment housing these reed blocks.

The peripheral spacing between the reflector members and the fixed chamber portions in each of the fixed compartments is designed to permit free passage of air when the expansible compart-' ment is either expanded or contracted.

Having thus described generally the structural arrangement of the present invention, its prin cipal object is the provision of combination sound chambers having fixed volumes, one for the treble reeds and another for the base reeds, whereby the sound waves emanating from the air-pressure operated reeds are first directed inwards through resonant, gradually inwardly enlarging exterior chamber portions, whereupon they are reflected in outward direction by means of resonant, deeply dion operated by air pressure, and which soundreflecting means are adapted to readily respond to sound vibrations produced by said elements.

A further object of the present invention is:

to provide in an accordion type instrument having pressure operated sound producing elements associated with the fixed compartments of the instrument, thin walled, resonant, smooth faced, continuous sound reflecting means with rounded corners and edges so disposed within the instrument that their open ends are directed outwardly in respect to the instrument body, and which sound reflecting means are fioatingly suspended so that their whole bodies freely and unrestrictedly respond to sound vibrations produced by the sound producing elements of the instrument and direct sound emanating from said elements in outward directions. I

A further object 01' this invention is to'provide for the aforesaid sound reflecting means, suitable suspension means which facilitate substantially free movement of said sound reflecting means so that they unrestrictedly respond to sound vibrations produced by the sound producing elements of the instrument.

The foregoing and still further objects and important advantages of this invention will be come more fully apparent from the ensuing description, in conjunction with the accompanying drawings, wherein:

Fig. 1 represents a typical transverse cross section through the instrument of the present invention;

Fig. 2 is a section taken on line 2-2 of Fig. 1 with portions of one of the sound reflecting members broken oif and with the expansible member removed;

Fig. 3 is a fragmental section taken on line 3-3 through Fig. 2;

Fig. 4 is a partial interior view of the sound refleeting member for the treble reeds;

Fig. 5 is a partial top view thereof;

Fig. 6 is a section taken on line 6-6 of Fig. 4; and

Fig. '7 is a fragmental, enlarged section taken on line I--I of Fig. 1 illustrating the base reed sound reflecting member.

Referring now more specifically to the figures, numeral Ill denotes one of the fixed compartments of an accordion for housing the treble reeds and which compartment has an extension I l supporting a keyboard I I for operating valves controlling the operation of the treble reeds. Numeral I2 indicates the other fixed compartment of the instrument which houses the base reeds, and numeral I3 denotes the expansible compartment or bellow section of the accordion. Fixed compartment I2 is provided with a keyboard I2' for actuating valves controlling the operation of the base reeds.

As is well known, an accordion is played by the manual expansion and compression of bellows l3, whereby air is forced into the instrument and expelled therefrom, respectively, while simultaneously the various keys of the keyboards are depressed and released to open and close suitable valves which control the passage of air through the vibratory reed elements supported in reed blocks. Again referring to Fig. l, keyboard II is composed of a plurality of keys HI and I5 connected by means of a system of levers I6 to the different valves I I which control openings II' forming passages through reed block support I9 to the several treble reed blocks I9. These reed blocks are diagrammatically shown in plan view in Fig. 2. Reed block supporting member I8 extends between the four walls of fixed com partment In and forms a closure for a resonant chamber indicated at 20, reference to which will be had presently.

Fixed compartment I2 of the instrument is also provided with a reed block support 2| which extends to all four walls of the compartment and is provided with apertures 22 controlled by valves it operated by means of a lever arrangement 24 by way of the keys of keyboard I2. Supported by'member 2| are base reed blocks 25 and 26. Reed blocks 25 extend partly into bellows I3 while reed block 26 is much lower.

The aforesaid description of the arrangement of reed blocks, the outer fixed compartment I0 and I2 and bellows I3 is common to most accordion structures. In heretofore produced instruments of that type very little attention has been devoted to the quality of their acoustic properties, consequently these properties may not be generally considered ideal from the point of view of sound, resonance, value and volume. The present invention is intended to improve these acoustic properties: by the employment of specially designed resonant chambers or sound boxes which include resonant sound receiving and sound propagating or sound reflecting members. In fixed compartment I0 there is arranged the already-mentioned chamber or sound box 20 composed of an outer chamber portion 21, the walls of which are curved from the interior end of compartment II] towards the exterior end, which latter end terminates at supporting member I8. That sound chamber portion resembles substantially an inverted funnel with the smaller end directed outwardly. The walls of the chamber portion 21 are relatively thin, having finely executed smooth surfaces, which gradually curve. All corners of chamber portion 2'! are carefully rounded, as shown in Fig. 2 at 28.

Within the larger end of chamber portion 21 there is located a sound reflector 29. This reflector comprises a relatively deeply dished, substantially oblong, thin-walled structure, the surfaces of which are carefully finished and the corners and the connections between the flanges and the bottom being smoothly rounded, as indicated at 30 and 3i in Figs. 2, 4, 1, 3 and 6. Also the outer edges of the sound reflector are rounded as indicated at 32. This sound reflector is held removably in position at its short sides by means of spring clips Band 34 which are perforated to receive the heads of screws 35 extending from the reflector body and which clips are attached to angles 36 and 31 supported by posts 38 and 39, respectively. The suspension of the sound reflector is so designed as to assure the refiectors responding freely and fully to any sound vibration. Reflector 29 partly encloses reed blocks I9 and is spaced from these blocks by suitable spacer buttons 40, clearly seen in Figs. 1, 2 and 3. The rounded edges of reflector 29 are also spaced peripherally from the walls of chamber portion 21, preferably by means of suitable spacer buttons 4| shown in Figs. 1 and 2. The circumferential edges of sound reflector 29 are substantially parallel with the corresponding wall parts of chamber portion 21 so that the spacing between these two instrumentalities is uniform throughout.

In fixed compartment I2 a sound chamber isformed by the walls of that compartment, the interior surfaces of which are also carefully executed to a fine smoothness, and wherever curva tures occur, such as in the bodies of the walls indicated at 42 and 43 in Fig. 1, as well as at the corners of the compartment, these curvatures are produced with great care so as to eliminate any undue obstruction to the free passage of sound.

Reed blocks and a portion of read block 26 are partly enclosed by a sound reflector 44, which latter comprises a thin-walled, deeply dished structure having smooth surfaces and carefully rounded corners 45. Edge 46 at the open end of the reflector is also rounded. Reflector 44 is suspended within resilient clips 46, shown in Fig. 7, by means of screws 41 passing through the clips. These clips are attached to angles 48 supported by posts 49. These posts extend from and are secured to reed block support 2|. The suspension of reflector 44 by means of resilient clips 46 assures a free response of the reflector body to sound vibrations. It will be noted that the outer opening of fixed compartment [2 is of a much lesser area than the interior end of that compartment, and that the rounded outer edge portions 46 of reflector 44 are substantially parallel with the interior surfaces of compartmentlZ.

It is being emphasized that both reflector members 29 and 44, as well as their corresponding chamber portions in their respective fixed compartments Ill and 12 are highly resonant, and that they readily respond to sound vibrations emanating from the vibratory reed elements when the latter are subject to air under pressure by the action of bellows l3.

Operation When the instrument is played by the repeated expansion and compression of the bellows and the operation of the keys, the vibratory reed elements are caused to produce sound waves. These sound waves are conveyed first towards the interior of the instrument through the inwardly funneled outer sound chamber portions. These inwardly propagated sound waves are now reflected by resonant reflectors 29 and 44 and are directed by them outwardly. The spacing between the sound reflectors and the outer chamber portions permits the free passage of air into and out of the instrument. The fact that both the outer chamber portions as well as the reflectors are so arranged as to readily respond to the sound vibrations induced by the air-actuated reeds, not only the tonal quality of the instrument is improved, but also the volume of the emitted sounds is substantially increased, where by the overall tonal efficiency of the instrument is materially improved over those produced by existing similar instruments.

Structure The attachment and suspension of sound reflectors 29 and 44, while shown in their presently preferred form, may be altered, depending upon the material used for these instrumentalities, but in any event their suspension. and position must be such that a free passage of air is assured between their walls and those of the outer chamber portions and that they readily respondto sound vibrations. The material from which the outer chamber portions and the reflectors are constructed is subject to considerable variations, depending upon the type and size of instrument in which they are to be used, but are preferably made of either suitable wood, plastic, metals and alloys of th lightness and thickness necessary to produce the desired sound and volume effects required. As may be observed, the combined outer chamber portions and the corresponding sound reflectors are constructed in a manner similar to that of sound boxes employed in string instruments.

Sound chambers The tone quality of musical instruments depends largely upon the correct response of their structure to the sound vibrations produced. The eflectiveness of such response is considerably enhanced in many instruments by the employment of resonant sound chambers or sound boxes, provided that the latter are designed correctly for the entire desired range of sound vibration frequencies to be used. One of the important factors governing the resonancy of the sound chamber, which resonancy in turn controls the tone quality of the instrument, is the volume of such sound chambers.

For high frequency sound vibrations, sound chambers of relatively small volume are employed, such as for instance for a violin, whereas instruments producing sound vibrations of a lower frequency or lower pitch must have a much larger volume, such as used in the base violin.

Inasmuch as the average pitch range of the treble reed elements located in one of the fixed accordion compartments of the present invention is materially higher than the pitch range of the base reed elements, housed in the other fixed compartment, the sound chamber for the treble reeds will be of a substantially lesser volume than the sound chamber for the base reeds. Thus it becomes quite obvious that the volumes of these two respective chambers are fixed for their different ranges of sound vibration frequencies.

Conclusion While in the foregoing specific structures of the present device were described and discussed. these structures are subject to considerable variations as and for the reasons already indicated. Therefore such changes, variations and improvements are to be considered to reside within the scope of the present invention, as defined by the annexed claims.

I claim:

1. The combination with an air-pressure-operated musical instrument having sound-producing elements responsive to air under pressure passing through them, of solid-bodied, continuous, resonant sound reflecting means freely suspended in rear of and spaced from said elements and, due to their free suspension, being adapted to respond to the sound vibrations and to reflect and convey sound produced by said elements in outward direction.

2. In an air pressure-operated musical instrument having sound-producing elements operative by air under pressure, resonant, smoothfaced, continuous sound reflecting means freely suspended about, spaced from and partly enclosing said elements and being capable of freely responding to sound vibrations produced by said elements and being further adapted to reflect sound and to convey and direct outwardly reflected sound produced by said elements.

3. 'In an air pressure-operated musical instrument having compartments of fixed and variable volumes, sound-producing elements in the compartment of fixed volume responsive to air under pressure produced by the operation of the compartment of variable volume, substantially dishshaped relatively thin-walled, smooth-faced, resonant, continuous and self-contained sound-reflecting means partly surrounding and being spaced from said elements, suspension means for said sound-reflecting means adapted to facilitate unrestricted vibration of the latter means induced by sound emanating from said elements, said sound-reflecting-means being positioned to convey sound. produced by said elements in outward direction.

4. In an air pressure-operated musicalinstrument having sound-producing elements operative by .air under pressure, a dished, resonant, continuous, self-contained soundereflecting memher so suspended about and spaced from said elements that it will convey sound producedby the latter in. outward direction, and suspension means for said member facilitating the latters bodily, unrestricted response to sound vibrations.

5. In an air pressure-operated musical instrument as per claim l, said member being of .a fixed volume.

6. In an air pressure-operated musical instrument asper claim 4, said member comprising a relatively thin-walled structure, the bodycand the peripheral edges of which are substantiallyiree.

"i. In a musical instrument, at least two .sets of keyboard-ope ated vibratory sound-producing elements responsive to air under pressure, two relatively rigid. compartments of fixed volumes; an operative, cx-pansible compartment ofvari- :able volume detachably connecting the rigid compartments; each of the rigid compartments having outwardly directed, smooth resonant walls; sound-reflecting, relatively thin-walled, resonant, dished members spacedfromthe .walls of said rigid compartments and surrounding substantial parts of but being spaced from said elements, the open ends of said members being free to vibrate and being directed outwardly.

8. In a musical instrument as per claim '7, said sound-reflecting members having curved interior and exterior surfaces at their inner ends and curved edges, the latter being substantially in parallelism with corresponding edges of the rigid compartments.

9. In a musical instrument as per claim 7, said sound-reflecting members being not only. spaced from said elements in all directions, but also peripherally from the walls of said rigid compartmen-ts.

10. The combination with an accordion structure of the type indicated, of a dished, freely suspended resonant sound reflector spaced from and surrounding with its dished walls the sound-producing elements of the accordion and being adapted to not only convey sound from such elements in outward direction, but to bodily respond to sound vibrations.

11. In an accordion having two fixed compartments provided with perforated supporting members and an expansible compartment connecting .spaced from the walls of said fixed compartments,

the walls of said reflecting members being directed outwardly.

12. In an accordion, as per claim 11,' the edges of the open ends of saidreflecting members being substantially parallel with'at least some :portions of the walls of the fixed compartments.

13. In an accordion, as per claim 11., 'theledges of the open ends of said reflecting members being substantially parallel with at least some portions of the walls of the fixed compartments, the open ends of said reflecting members being substantially distanced from said supporting members for the reed 'blocks.

14. In an accordion, as per claim 11 the edges of the open ends of said reflecting members being substantially parallel with at least some portions of the wallsofthe fixed compartments, the open ends of said reflecting members being substantially distanced from said supporting members for the reed blocks, and resilient 'supporting 'elements for said reflecting members detachably engaging the latter.

15. The combination with an accordion, om. resonant sound chamber having therewithin a dished, freely suspended, resonant sound reflector.

16. The combination with an accordion, of resonant sound chambers, one for the treble reeds and another for the base reeds, both chambers having freely suspended, dished, bodily resonant sound reflectors, the free walls of which being directed outwardly.

17 The combination with an accordion, ofresonant sound chambers, one for the treble reeds and another for the base reeds and wherein the sound chambers comprise exterior and interior portions, the latter forming dished sound reflecting structures freely suspended within said exterior portions and having their free open wall edges directed outwardly of the accordion.

18. The combination with an accordion, of resonant sound chambers for the treble and the base reeds, said chambers being of fixed volumes and including as one of their parts removably and freely mounted, dished soundrefiectors.

19. The combination with an accordion, of resonantsound chambers for the treble and the base reeds, said chambers being of fixed volumes and including as one. of their interior parts removably freely mounted sound reflectors, the latter comprising dished structures with their freeopen end edges directed outwardly.

20. The combination with an accordion, o'iresonant sound chambers, one for the treble reeds, another for the base reeds, each chamber being of a fixed volume and, comprising outer chamber portions and inner, removably and resiliently mounted dished sound reflectors spaced from said outer chamber portions. and having their free open wall edges directed outwardly.

ALFREDO FRONTALINI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,105,365 Pancotti Jan. .11, 1938 2,220,276 .Price Nov. 5, .1940 2,230,162 Lidblom Jan. 28, 1941 2,448,682 Pancotti Sept. 7, 1948 FOREIGN PATENTS Number Country Date 348,133 Italy May 12, 1937 

